The present invention relates to an input buffer, a semiconductor device and an engine control unit and, for example, relates to the input buffer, the semiconductor device and the engine control unit suited to execute fault diagnosis in real time while suppressing misdetection of a fault.
An engine control unit (ECU) which controls an engine is loaded on a vehicle such as an automobile, a motor bicycle and so forth. The engine control unit includes, for example, a microcomputer which outputs a control signal in accordance with button operation by a driver and a semiconductor device for electric power control (hereinafter, referred to as the electric power control semiconductor device) which controls driving of an electric parking brake (EPB) on the basis of the control signal.
Here, it is requested to the electric power control semiconductor device to control driving of the electric parking brake without impairing safety performance. In particular, it is requested to the electric power control semiconductor device to drive the electric parking brake in the same manner as that in a normal state or, at least, to prevent sudden stopping and sudden starting of the vehicle (that is, to shift the vehicle to a failsafe operation) by bringing the electric parking brake into a non-driven state even in a case where the input buffer which receives the control signal from the microcomputer has failed.
For example, a configuration disclosed in Japanese Unexamined Patent Application Publication No. 2003-307544 is adapted to selectively operate any one of clocked inverters which are arranged in parallel and prevents stopping of an operation caused by a fault by switching the clocked inverter to be selected to another clocked inverter and operating it in a case where the fault of one clocked inverter which is being selected has been detected.